Exploring Electric Fields and Dipoles

What is the expression for the electric field due to a dipole at a point along its axial line?

• E = (1/(4πε₀)) * (p/r⁴)

• E = (1/(4πε₀)) * (p/r²)

• E = (1/(4πε₀)) * (p/r³) + (1/(4πε₀)) * (p/r²)

• E = (1/(4πε₀)) * (2p/r³)

Calculate the electric potential at a point 2 meters away from a point charge of +5 μC.

• 2247.5 V

• 500 V

• 3000 V

• 1500 V

Describe the shape and direction of electric field lines around a dipole.

• Electric field lines only exist around positive charges.

• Electric field lines are straight and do not curve.

• Electric field lines around a dipole start at the positive charge and end at the negative charge, curving outward and forming lobes.

• Electric field lines start and end at infinity.

What is the torque experienced by a dipole of moment 2.5 × 10⁻⁴ C·m in a uniform electric field of strength 1000 N/C?

• 1.0 N·m

• 0.1 N·m

• 0.25 N·m

• 0.5 N·m

Explain the principle of superposition in the context of electric fields.

• Electric fields cannot be combined; they act independently.

• The electric field is only influenced by the nearest charge.

• The total electric field is the vector sum of the electric fields from individual charges.

• The principle of superposition applies only to magnetic fields.

If a dipole has charges of +q and -q separated by a distance d, what is the formula for the dipole moment?

• p = q - d

• p = q * d

• p = q + d

• p = q / d

How does the electric field due to a dipole vary with distance from the dipole?

• The electric field due to a dipole varies as 1/r² with distance from the dipole.

• The electric field due to a dipole remains constant regardless of distance from the dipole.

• The electric field due to a dipole varies as 1/r with distance from the dipole.

• The electric field due to a dipole varies as 1/r³ with distance from the dipole.

What is the potential energy of a dipole in a uniform electric field?

• U = p · E

• U = 0

• U = -p · E

• U = p + E

Sketch the electric field lines for a dipole and explain their significance.

• The electric field lines only exist outside the dipole.

• The electric field lines start and end at infinity.

• The electric field lines for a dipole are straight and parallel.

• The electric field lines for a dipole are curved, starting from the positive charge and ending at the negative charge, with denser lines near the charges.

If two point charges of +3 μC and -3 μC are placed 1 meter apart, what is the net electric field at the midpoint?

• 0 N/C

• 6 N/C

• -3 N/C

• 3 N/C